Improvements in printing with ink composition having volatile solvents



Dec. 4, 1962 IMPROVEMENTS IN PRINTING WITH INK COMPOSITIONS Filed 001;.15, 1959 R K. REMER HAVING VOLATILE SOLVENTS 2 Sheets-Sheet l INVENTOR.

fiaber/Z Earner,

Dec. 4, 1962 R. K. REMER 3,067,056

IMPROVEMENTS IN PRINTING WITH INK COMPOSITIONS HAVING VOLATILE SOLVENTS2 Sheets-Sheet 2 Filed Oct. 15, 1959 46 P0706164 I/UAOE C )1 01/02}?INVEN TOR. Edie/Z75 56/7266 BY ll Ill/ll l J AI'IJ'AIIAIVJMIMIJIJIJIA' IUnited, States Patent 3,967,056 IMPRDVEMENTS IN PRINTHNG WITH lNK COM-PQSITIGN HAVHNG VGLATELE SOLVENTS Robert K. Renter, 1814 Noyes St,Evanston, Ill. Filed Get. 15, 1959, Ser. No. 846,750 18 Claims. (Qt.11736) My invention relates, generally, to improvements and innovationsin methods and apparatus for printing web or sheet materials such asplastic films, paper, foils, non woven fabrics, netting and textilefabrics.

According to my invention an ink is dispersed or dissolved in achlorinated solvent which is retained in the lower portion of a tank orin a fountain. Means may be provided in the bottom of the tank orfountain for heating and controlling the temperature of the ink. Theetched or mechanically knurled printing cylinder of a rotogravureprinting unit is mounted in the tank or fountain so as to run in the inkbath at the proper depth. The 'web or sheet material being treated ispassed through the intaglio or rotogravure printing unit located in thelower part of the fountain and thereby receives a metered surfacedeposit of the ink or coating in the form of tiny dots characteristic ofintaglio or rotogravure printing. The ink may be applied as an over-allcoating or in the form of a design and/or words and numerals. Thevolatile chlorinated solvent is immediately vaporized after deposit,leaving behind a metered deposit of the ink composition on the surfaceof the web. The upper portion of the tank or fountain extends above theprinting unit so as to retain the vapors therein and is provided withcondensing means for condensing the solvent vapors so as to recover thesame and prevent them from leaving the foun tain. The web or sheetleaves the top of the tank in a substantially dry, solvent-freecondition.

It has been found that this particular printing or coating process ispractical when the ink is applied from a rotogravure or intaglio typecylinder. Because of the type of deposit laid down on the web from sucha cylinder in the form of multitudinous fine dots, it is possible toflash off and recover practically all of the chlorinated solvent used asthe vehicle. When the web being printed is a fibrous or absorptivematerial such as paper, the chlorinated solvent still vaporizes from thetiny dots before it becomes absorbed or picked up by the web. Thedeposit which is applied by an etched or rotogravure cylinder is veryuniform and by selecting the depth and screen size of the etching orknurling, the amount of the deposit or coating can be very closelycontrolled and accurately metered. The web being printed or coatedtravels at a fast speed which makes the process practical and economicalwithout requiring large and expensive drying equipment and tunnels suchas commonly are used in connection with rotogravure printing employingexpensive volatile solvents.

An object of my invention is a method of and apparatus for continuouslyprinting or coating a travelling web or sheet by depositing thereon asuitable ink or coating composition dispersed or dissolved in achlorinated solvent vehicle contained in a tank or fountain, the depositbeing applied by a rotogravure cylinder in such manner that the solventquickly evaporates therefrom and is condensed in the upper portion ofthe tank while the web leaves the tank in a substantially solvent-freecondition.

Another object of my invention is a method of and apparatus forcontinuously printing or coating a travelling web or sheet by passingsame over a rotogravure printing cylinder running in a bath of ink orcoating composition dispersed or dissolved in a chlorinated solventvehicle and then passing the web or sheet upwardly through an upperportion of the tank or fountain wherein the solvent Tree vapors evolvedfrom the bath and from the deposit applied to the web or sheet arecondensed and recovered while the web or sheet leaves the tank orfountain in a substantially solvent-free condition.

Another object of the invention is a method of and apparatus forprinting or coating polyethylene, polyvinyl and polyester films bypassing such films over a rotogravure or intaglio printing cylinderrunning in a bath of ink or coating composition dissolved or dispersedin chlorinated solvent vehicle in the bottom portion of a fountain, andcondensing in the upper portion of the tank or fountain the solventvapors which are evolved from the bath and from the printed or coatedfilm whereby the film leaves the fountain in a substantiallysolvent-free condition.

Another object of the invention is a method of and apparatus for makingcarbon paper without strike through by printing and depositing a coatingwhich will not rub 01f, by passing a continuously running web or sheetof paper over a rotogravure printing cylinder or coating roll running ina bath of carbon ink dispersed in a chlorinated solvent in the bottom ofa fountain and passing the web or sheet of paper out through the top ofthe fountain which is provided with a condenser for condensing solventvapors evolved from the bath and from the printed or coated paper whichleaves the fountain in a. substantially solvent-free condition.

Another object of the invention is an apparatus for printing acontinuously travelling web or sheet comprising a relatively deepfountain having a rotogravure printing unit disposed in the bottomportion thereof so that the printing cylinder runs in a bath of an inkor coating composition dissolved or dispersed in a volatile solvent,with heater means in the upper portion of the fountain above the levelof the bath for driving solvent off from the printed or coated web, andassociated condenser means for condensing solvent vapors so that they donot escape from the fountain and may be returned to the bath orseparately recovered.

Another object of the invention is a rapid method of printing onpolyethylene film in one or more colors with an ink that adheres firmlyto the polyethylene without any prior or separate heat-conditioning orchemical treatment of the film to make it take the ink, which method innowise impairs the normal heat-sealing properties of the polyethylene.

Another object of the invention is polyethylene film which has beenprinted or decorated in one or more colors without being subjected toany heat conditioning or chemical conditioning treatment and on thesurface of which the inks adhere firmly both to the surface of the filmitself and one ink on top of another ink when the film is printedcolor-on-color.

Another object of the invention is an inexpensive method of andapparatus for rapidly producing one-time carbon paper, without wickingwhich is the cause of strike through, by continuously passing a web ofpaper over a rotogravure printing cylinder disposed in the bot tomportion of a fountain containing a bath of one-time carbon ink dissolvedor dispersed in chlorinated solvent, rapidly releasing solvent vaporsfrom the deposit applied to the paper and condensing the evolved solventin the upper portion of the fountain above the level of the bath so asto recover the same While the one-time carbon paper produced leaves thefountain in a substantially solvent-free condition.

Another object of the invention is a one-time carbon paper characterizedby its excellent reproducing properties and a high resistance to rub-01for smudging.

Another object of the invention is a new and improved ink compositionfor printing on films having non-ab- 8,0 3 sorbent waxy-like surfacessuch as polyethylene, polyvinyl and polyester films.

Another object of the invention is a new and improved carbon inkcomposition adapted to be dissolved or dispersed in a hot solvent foruse in printing one-time carbon paper.

Certain other objects of the invention will in part be obvious and willin part appear hereinafter.

For a more complete understanding of the nature and scope of theinvention, reference may now be had to the following detaileddescription thereof, wherein certain illustrative examples andembodiments are set forth.

In the accompanying drawings:

FIG. 1 is a diagrammatic view showing one type of apparatus andillustrating one method whereby my invention may be practiced;

FIG. 2 is a top plan view of a fountain which forms the bottom part ofan apparatus constituting another embodiment of the invention and whichhas been successfully used to practice the same;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2 and showing inaddition the bottom end of a condenser unit that fits on top of thefountain;

FIG. 4 is a vertical sectional view through the condenser unit whichfits on top of the fountain of FIGS. 2 and 3;

FIG. 5 is in FIG. 4;

FIG. 6 is a detail sectional view on enlarged scale taken on line 6-6 ofFIG. 2;

FIG. 7 is a fragmentary detail sectional veiw on enlarged scale on line77 of FIG. 4; and

FIG. 8 is an enlarged detail section taken online 8--8' or FIG. 4.

In FIG. 1 a fountain or tank is indicated at 5' which may be formed ofsuitable material such as stainless steel and in which is disposedadjacent the bottom thereof a rotogravure or intaglio printing unitcomprising a printing cylinder 6, an impression cylinder or roll 7, anda doctor blade 8. Any suitable intaglio or rotogravure printing unit ofknown type may be usedfor the purpose of this invention. The printingcylinder 6 may have an over-all printing surface or it may carry adesign wherein there are printing areas and non-printing areas. Thecylinder 6 may be an etched cylinder or a mechanically knurled cylinder.If a knurled cylinder or an over-all etched cylinder is used and it isdesired to have nonprinting areas, such areas may be obtained bytreating them with a film-forming material such as Teflon(tetrafluoroethylene polymer).

One or both of the cylinder 6 and 7 may be electrically heated in a wellknown manner by one of several commercially available electrical heaterunits in order to hasten the evaporation of the solvent and the settingof the coating or printed matter on the web or sheet. An electric heaterelement 9 of known type is shown wound on the support shaft for roll 9.

The lower portion of the printing cylinder 6 runs in a liquid bathcontained in the bottom of the fountain or vessel 5 comprising an ink orcoating composition dissolved or uniformly dispersed in a-chlorinatedsolvent. A number of formulations for such a bath will be de-' scribedin detail hereinafter in the examples. When a relatively heavy over-alldeposit or coating is to be deposited on a web (e.g. as by a cylinderhaving a 35 to 65 line screen) the bath in the bottom of the fountain 5should usually be maintained at or about its boiling temperature so thatthe solvent vapors will be rapidly evolved from the surface thereof andfrom the deposit of the bath which is applied to the travelling film orweb 10 as it passes through the printing or coating unit. On the otherhand, when only light over-all printing or small design areas areprinted on the Web 10 (e.g. as a cylinder having 165 to 200 linescreen), then it usually will not be necessary to heat the ink bathabove room temperature.

a top plan view of the condensing unit shown When heating is desired,the temperature of the bath may be controlled in any one of a number ofways such as by passing a heating fluid (gas or liquid) through a coil11 located in the bottom of the fountain. Any fluid heating medium ofsuitable heat transfer and other physical characteristics may be used,such as steam, oil or Dowtnerm (eutectic mixture of phenyl ether and26.5% of diphenyl oxide having a boiling point of 258 C.). A condensercoil 12 is fitted around the upper portion of the fountain 5 so as tocool or chill the upper portion of the fountain above the printing unitso as to condense the solvent vapors evolved from the bath and from thedeposit of the bath applied to the web 10 and cause the condensate torun down the side walls of the fountain on the inside. It will beunderstood that any suitable and known type of condenser may be used,either external or internal, and any suitable heat transfer fluid can bepassed through the condenser 12 at the proper temperature and rate offlow. However, for purposes of economy cool or cold water willordinarily be used as the condensing medium.

A supply roll of the web or sheet material to be printed is indicated at13 and the wind-up roll of the printed or coated sheet or web materialis indicated at 14. As is well understood in the art, the wind-up roll14 will ordinarily be driven, as well as the rolls of the printing orcoating unit in the fountain 5. The web or sheet 10 is guided into thefountain 5 by passage over a freely rotating guide roll 15 and passesout from the fountain over a freely rotating guide roll 16.

An ink composition suitable for dissolving or dispersing in achlorinated solvent to make a bath to be used in the fountain 5 forprinting polyethylene film is set forth in the following example:

The foregoing ink formulation may be prepared in a ball mill or in acolloid mill in accordance with known ink-making techniques.Approximately 35 parts of the ink formulation are dissolved in 65 partsof chlorinated solvent, preferably trichloroethylene. Other chlorinatedsolvents which may be used include perchloroethylene,pentachloroethylene, ethylene dichloride, trichloromethane,dichloromethane and methylene chloride. Commercial grade chlorinatedsolvents may be used alone or in suitable mixtures.

When a relatively heavy over-all coating or deposit is to be applied tothe web 10 by the printing cylinder 6, steam or other heating medium ispassed through the heater unit 11 so as to raise the temperature of thebath to about the boiling point (e.g. F. in the case oftrichloroethylene) so that the lower portion of the fountain 5surrounding the printing unit is filled with hot solvent vapors. If onlyprinting or small-area designs are being printed, it is not necessary toheat the bath. As the printing cylinder 6 revolves in the solvent bath afilm of the liquid adheres to the surface thereof which the doctor 8removes from any non-printing areas and the excess from the printingareas in the usual manner, and thereafter the composition is transferredfrom the small depressions constituting the printing areas onto theundersurface of the film 10 as it passes through the bite or kisscontact between the printing cylinder 6 and the impression roll 7. Thechlorinated solvent almost immediately escapes or is driven off from thefilm, leaving the ink set and adhered to the film. Sufficient condensingwater is passed through the condenser 12 so as to chill or cool theupper portion of the fountain 5 to the point where the solvent vaporsare condensed on the inside and do not escape from the fountain. Whenthe printed film It) leaves the fountain 5 It is in a substantiallysolvent-free and dry condition and may be rewound immediately. If theink composition is highly plasticized the final setting of the ink orcoating may be hastened by means of a suitable drier indicated at 17which may take the form of infra-red lamps, heated air blowers, orheated idler rolls.

When the apparatus is operated properly with the ink bath being heatedwhen required, practically no solvent leaves the fountain 5, andtherefore while the bath becomes gradually depleted of the ink orcoating composition dissolved in the solvent as it is deposited on andcarried away on the travelling web or sheet very little solvent is lost.A supply or extender tank 13 is mounted on the side of the fountain 5for containing a supplementary supply of the ink or coating composition,which preferably is dissolved in some of the chlorinated solvent so asto make up a concentrated solution. The supply tank 18 is provided withan outlet conduit 20, the bottom end of which passes through the sidewall of the fountain 5 adjacent the bottom thereof, as shown. The flowof the concentrate is regulated by means of a valve indicated at 21.

if it is desired to print the film 10 in more than one color, the filmIt may be passed through additional printing units of the same type asshown in FIG. 1 so that the film is printed either in registration or ina color-on-color relationship, as is well understood in the art.

7 The ink formulation of Example 1 may be varied in several respects.

While the chlorinated rubber and butadiene-acrylonitril copolymer is apreferred resin combination, either of these may be used alone and othersynthetic rubber polymers and copolymers and resins soluble inchlorinated solvents may be employed, e.g. styrene'isobutylenecopolymer. Likewise, methyl abietate and diallyl phthalate is apreferred plasticizer combination, but other compatible plasticizers maybe used. Other antioxidants may also be used as well as other pigments.Also dyes which are soluble in chlorinated solvents may be used in placeof pigments, if desired.

Other films besides polyethylene that may be printed by the processdescribed in connection with FIG. 1 include cellulose acetate,regenerated cellulose, chlorinated rubber (Pliofilm), vinylidenechloride copolymer (Saran), polyvinyl acetate and polyester films.

Another ink formulation which is particularly adapted for printing onpolyethylene is the following:

Example 2 Parts by weight Nylon scrap (thread) 7-0 Cresylic acid 30Hausa Yellow (yellow pigment) 10 The nylon is dissolved in the cresylicacid and thenthe pigment is milled in. Approximately 110 parts of themixture are added to 90 parts of chlorinated solvent (trichloroethylene)so as to make up a bath suitable for use in the bottom of the fountain5.

Still another ink-chlorinated solvent formulation for printing onpolyethylene film according to the present invention is the following:

Example 3 Parts by weight Chlorosulfonated polymer of ethylene (HypalonPhenolic maleic acid ester resin (Super- Beckacite 1001, Reichhold) 20Chlorinated diphenyl (Arochlor) 20 The following is a suitableformulation for an adhesivecomposition for manufacturing pressuresensitive adhesive tape:

, polyethylene or Saran.

Example 4 Parts by weight Methyl abietate 15 Alpha-methylstyrene polymer(Dow Resin 276V2) 15 Hydrogenated rosin (Staybelite Ester 10, Hercules)15 Chlorinated rubber (67% chlorine) 15 2,2-methylenebis(4-methyl-6-tertiary butylphenol), heat and light stabilizer Sixty-twoparts of this formulation are dissolved in 38 parts of trichloroethyleneto prepare a bath suitable for use in the apparatus shown in FIG. 1 forapplying a pressure sensitive adhesive coating to one side of atravelling Web of plastic film such as cellophane, cellulose acetate,The same formulation may also he applied to advantage to a web ofplastic, non-woven fabric, glass fabrics, textile fabrics or paper.

A suitable carbon ink formulation for making one-time carbon paper inthe apparatus shown in FIG. 1 is shown in the following example:

Example 5 Parts by weight Armid O- 30 Steararnide 6% Oleamide 91%Linoleamide 3% Sugar cane wax 3O Chlorinated paraflin 5 Carbon black lAlizarin blue 1 2,2-methylenebis (4 methyl-6-tertiary butylphenol) 1This formulation can be ball milled or milled in a colloid mill and 68parts of the ink can be dissolved in 32 parts of trichloroethylene tomake up a bath for use in the apparatus of FIG. 1.

The following formulation is specially adapted for application to a webor sheet for depositing thereon an electrically conductive coating: 7

Example 6 Parts by weight Acetylene carbon black 25 Chlorinated parafiin20 Methyl abietate 20 Lithium nitrate (or lithium chloride) 1t)Seventy-five parts of this ink composition may be dissolved in 25 partsof chlorinated solvent to prepare a fountain bath which may be appliedinthe apparatus shown in FIG. 1 in accordance with the method of operationdescribed above to provide printed circuits, printed dry cells andvarious electrical circuitry, The following is an example of a magneticcoating composition which may be applied to paper or other sheetmaterial according to the process of this invention:

Example 7 Parts by weight Carbonyl iron powder (or any iron oxidepowder) 25 Chlorinated paraffin 25 Methyl abietate 25 Seventy-five partsof this formulation may be dissolved in 25 parts of chlorinated solventand used as the fountain bath in the apparatus of FIG. 1. Afterapplication to a sheet or web the resulting coating may be magnetized.

The apparatus and method of the present invention may also be usedadvantageously for the continuous printing of metal foils such asaluminum foil. Such a foil may be passed through the apparatus shown inFIG. 1 and printed on the underside with an ink having the followingformulation:

Example 8 Parts by weight Ethyl cellulose (low viscosity) 2OAlpha-methylstyrene polymer (Dow Resin 276V2) 10 Parts by weight Methylabietate 10 Azo Oil Blue B Forty-five parts of this formulation aredissolved in 55 parts of trichloroethylene or other chlorinated solventand used as the fountain solution in the apparatus of HG. 1.

The following ink composition in chlorinated solvent is particularlyadapted for printing on films of cellulose acetate and Mylar polyesterfilms using the apparatus of FIG. 1:

Example 9 Parts by weight Ethylene dichloride 45 Methylmethacrylate(Plexiglas) 45 Glacial acetic acid 10 TiO pigment 10 The apparatus shownin FIGS. 27 has been used to advantage in practicing the invention andit represents a preferred working embodiment of the invention. Theapparatus comprises a fountain indicated generally at 25, on top ofwhich is mounted a condenser indicated generally at 26. If desired,additional condenser units up to any desired weight, may be added toprovide additional condensing capacity and a longer time for theprintedweb to be heated if desired before it leaves the apparatus.

The fountain and condenser 26 may be fabricated from sheet metal of atype which will withstand chlorinated solvent and solvent vapors. Thefountain 25 has a bottom 27 and side walls 23'. A rectangular frame 39sets into the upper ends of the vertical side walls 28 and supports thebed or bottom of the fountain indicated at 31. The frame 30 on two sideshas a U-shaped cross section so as to form channels 32 as indicated inFIG. 3 having laterally projecting flanges 33 integrally formed thereon.The opposite sides of the frame 30 also have U-shaped troughs 34- (FIG.6), laterally projecting flanges 35 and a horizontal inner flange 36which supports a vertical flange 37.

The U-shaped troughs or channels 32 and 34 communicate with each otheraround the periphery of the frame 30 for the purpose of providing adrain into which condensed solvent is collected and from which it may bedrawn off through an outlet connection 38 (FIGS. 2 and 3). Referring toFIG. 6, it will be seen that the condensate first drips onto the innerhorizontal flanges 36 and then runs off these flanges into thecommunicating troughs 34 and 32. The gasket 60 serves to space thebottom of the condenser 26 off the flanges 36 so as to allow thisdraining action.

The bottom of the bed 31 is generally horizontal while the opposite endsare upwardly curved as shown in FIG. 3. Ink or coating compositions maybe introduced into the fountain through an outside riser 40 having acover 41 hinged to the top thereof and adapted to be closed by means ofa wing nut 42. The bottom end of the riser 40 communicates with ahorizontal connection 43 which opens into the bed of the fountainthrough an opening 44.

The top edges of the vertical flanges 37 slope downwardly from oppositeends toward the middle into semicircular recesses 45 as shown in FIG. 3.The recesses 45 serve to provide clearance for the shafts or journals onthe opposite ends of a rotogravure or etched cylinder 46.

It will be seen that the fountain 25 has a hollow construction under thefloor 31 and this is for the purpose of holding a hot liquid such asoil, water or Dowtherm when it is necessary or desirable to heat thecontents within the fountain as when printing an overall coating on theweb W. The heating liquid may be introduced into the fountain throughthe connection 47 and withdrawn through the discharge connection 48. Itwill be understood that instead of using a liquid, or a gas such assteam, for heating the fountain that other heating means can be usedsuch as an electrical resistance heater or a radiant heater. Ifflexibility of the unit is' not important the false bottom 31 may beomitted along with the connections 47 and 48. Even though the unit hasno provision for heating the ink bath, it may still be heated exteriorlyand circulated by suitable pump means.

The condenser unit 26 is generally rectangular in shape and has ahollow-walled construction. The exterior walls of the condenser unit areindicated at Three of the inner walls are the same and are indicated at51. The fourth inner wall is different in that it is corrugated asindicated at 52 so as to provide additional condensing or coolingsurface since it is adjacent this wall that the printed web or filmpasses upwardly on its way out of the condenser unit. The speed at whichthe various webs may be printed or coated may be increased by using aheater of known type which is indicated diagrammatically at 53. Thisheater is juxtaposed to the corrugated wall 52 and is somewhat curved orrounded on that side and has a smooth surface over which the non-printedor non-coated side of the web W may ride and receive heat. Thus, thefunction of the heater 5?; is to present a hot surface for heating theprinted web W. Advantageously, the front surface of the heater 53 overwhich the web passes may be perforated with numerous pores or openings59 as shown in FIG. 8 through which air may be blown. Air may beintroduced into the heater 53 through the pipe 69 under suflicientpressure to discharge it through the openings 59. The air may be heatedwhen introduced and will be heated as it passes through the heater 53.The air assists in removing residual solvent from the printed web and insetting the deposited ink. Depending on the volume and pressure, the airor other gas discharging through the openings 59 serves as an aircushion between the travelling web and heater surface.

Coolant such as cold water or brine is circulated through the condenserunit 26, being introduced at the top adjacent one corner through theinlet 5'4 and being Withdrawn from the bottom adjacent the oppositecorner through the outlet 55. hollow walls are closed off as indicatedat 56 and 57 in FIG. 4. The bottom of the condenser unit is providedwith a peripheral flange 58 which is dimensioned to meet or fit oppositethe laterally extending flanges 33 and 35 on the frame 3% of thefountain as shown in FIG. 3 with a gasket 60 fitting therebetween.

The rotogravure roll or cylinder 46 and its impression roll 61 arelocated in the lower portion of the condenser 26 with the bottom of thecylinder 46 running in the fountain bath. The journals or supportingshafts on the opposite ends of the cylinders 46 and 61 project throughthe side walls of the condenser unit 26 through aligned sets of openingsprovided therein as shown in FIG. 7. On the interior of the oppositeside walls of the condenser unit an integral bearing plate formed of amaterial such as Teflon is located as designated at 62. Each of theTeflon plates 62 has an integral upper sleeve bearing 63 and an integrallower sleeve bearing 64. These bearings project through the circularopenings provided therefor in the opposite side walls of the condenserunit. The journals 65 on opposite ends of the rotogravure cylinder 46carry on their outer ends a pinion gear 66 which meshes with a piniongear 67 mounted on the outer end of the journal 68 supporting theimpression roll 61. The rotogravure cylinder 46 and impression roll 61are driven in a known manner. A doctor blade 7a is provided for removingexcess ink or coating composition from the rotogravure cylinder 46.

The web W of material to be printed is introduced into the apparatusover a guide roll 71 and is guided out of the unit over a guide roll 72.The web W passes between the rotogravure cylinder 46 and the impressionThe top and bottom ends of theroll 61 so as to receive on its undersidethe ink or coating composition deposited thereon from the rotogravurecylinder 46.

Preferably the printing cylinder 46 is arranged to be heated such as bythe insertion therein of an electrical resistance heating element 7? ofknown type such as a calrod heater element of suitable shape. The heaterelement may be used to heat the printing cylinder 46 to a temperature of180 F., for example. The purpose in having the cylinder heated is toexpel or volatilize the solvent faster from the dots which are depositedupon the web W and to cause the dots to flow and merge one with anotherinto a continuous film. Also, heating renders the ink in the wellshighly fluid and facilitates their emptying. The heater 53 in the upperportion of the condenser unit 26 may also be heated to a similartemperature, i.e. around 180 F., for example. By heating the printingcylinder 46 and using the heater 53 it is possible to operate theprinting or coating machine at higher speeds, especially when air isblown through the perforated surface of the heater 53.

It is sometimes desirable that the web W be heated when printed and thismay be conveniently accomplished by use of a radiant heater 86 disposedjust ahead of the guide roller 71. One or more such heaters may beprovided on the same, or on opposite sides of the web.

The Width of the webs which are printed or coated may be varieddepending upon the dimensions of the machines which are used. Thesemachines may be used to print or coat several spaced webs of kraft paperhaving widths of about 1 inch, and after such webs have passed throughthe printing unit they may be twisted into paper cord or twine of thetype that is used in manufacturing rugs, binder twine, show stitchingcords and the like. Sets of twisting rolls for twisting paper into suchcords are known and in use. Such sets of rolls of known type may belocated within the fountains or tanks of the apparatus shown in FIG. 1or in FIGS. 2-7.

Chlorinated solvents are used in this process for a number of reasons.They vaporize readily at low temperatures since they are low boilers,e.g. between about 104 to 160 F. Since the vapors are much heavier thanair they settle rapidly into the bottom of the condenser units. Thesevapors condense easily and if desired for use in other formulations maybe readily reclaimed by distilling and condensing. Chlorinated solventsare in the nature of dry solvents which do not wet or hydrate the webseven if the web happens to be a highly porous and absorptive materialsuch as newsprint. When these chlorinated solvents are heated they havevery high dissolving or suspending capacities for materials used in theink or coating compositions including resins, fillers and pigments. Suchmaterials dissolve or disperse readily in chlorinated solvents to a muchhigher or greater extent than they can be dissolved or dispersed inordinary solvents. This high solubility and dispersibility is due to thecombined solvent power and the heat. In practice, resins, fillers andpigments and other materials which are used in the inks or coatingcomposition to be applied in accordance with the present invention aremilled in the heated phase into or in the presence of hot chlorinatedsolvent and then the compositions may be allowed to solidify. When theyare to be used, the solidified compositions may be heated and thenthinned or extended as desired with additional hot chlorinated solvent.By following this procedure, it is possible to easily provide inks orcoating compositions which contain up to as much as 50 to 60% solids. Inthe usual cold ink or coating compositions the solvent phase usuallydoes not exceed 20% by weight.

Chlorinated solvents are non-polar and by the incorporation therein ofvarious known anti-static chemicals or agents they will serve to changeor convert the polarity of a web such as newsprint from a negativecharge to a positive charge while being printed or coated in accordancewith this invention. This conversion or change in electrical charge isfacilitated by having the impression roll formed of Thiokol, Teflon, orsilicone rubber materials which are loaded with graphite or molybdenumdisulphide. By employing anti-static chemicals or agents in thechlorinated solvents and by also forming the impression roll of one ofthe anti-friction materials mentioned above, it is possible to eliminateor substantially prevent the wicking action normally associated with apressure printing operation such as is involved in a rotogravure orrotogravure printing unit.

In View of the teaching contained in the foregoing examples, thoseskilled in the art will be able to make and use either the compositionsspecifically disclosed herein or probably such modified formulations asmay be required for their needs without departing from the spirit andscope of the present invention.

This application is a continuation-in-part of my copending applicationSerial No. 624,385, filed November 26, 1956, and now abandoned, which inturn was a continuation-in-part of my prior application Serial No. 367,-206, filed July 10, 1953, and now abandoned.

What is claimed as new is:

l. The method of rotogravure printing a web which comprises, conductingthe web in a continuous manner in printing contact with a non'immersedportion of a rotogravure cylinder only the bottom portion of whichrotates in a bath of ink dispersed in chlorinated solvent maintained ata temperature at which said solvent is rapidly volatilizing, saidrotogravure cylinder being disposed in the bottom of an enclosedfountain provided with superposed condensing means and having animpression cylinder associated therewith for holding said web in saidprinting contact, passing the printed web upwardly through saidcondensing means so as to leave said fountain in a substantiallysolventfree condition, and condensing said solvent at a rate sufficientto prevent escape of solvent vapor out of the top of said enclosedfountain.

2. The method of claim 1 wherein the condensed solvent is collected andremoved so as not to return directly into said bath.

3. The method of claim 1 wherein the condensed solvent is returned tosaid bath and additional ink or coating material is added to said bathso as to make up for the amounts carried away on said web.

4. The method of claim 1 wherein said web is paper.

5. The method of claim 1 wherein said web is a film selected from thegroup consisting of polyethylene, polyvinyl and polyester films.

6. The method of claim 1 wherein said solvent is trichloroethylene.

7. The method of rotogravure printing a web which comprises, conductingthe web in a continuous manner in printing contact with a non-immersedportion of a rotogravure cylinder only the bottom portion of whichrotates in a bath of ink dispersed in chlorinated solvent maintained ata temperature at which said solvent is rapidly volatilizing, saidrotogravure cylinder being disposed in the bottom of an enclosedfountain provided with superposed condensing means and having animpression cylinder associated therewith for holding said web in saidprinting contact, passing the non-printed side of said web over a heatedsurface while the printed side passes in close proximity to a condensingsurface without contacting the same, and condensing said solvent at arate sufilcient to prevent escape of solvent vapor out of the top ofsaid fountain.

8. The method of rotogravure printing polyethylene film which comprisespassing polyethylene through a printing unit having the bottom portiononly of the rotogravure cylinder running in an ink bath containingchlorinated solvent and heated at least approximately to boiling.

9. The method of making carbon paper comprising passing a web of paperthrough a printing or coating anemone i unit running in a fountain bathcontaining carbon ink dispersed in a chlorinated solvent and heated atleast to approximately boiling.

10. The method of printing polyethylene film comprising passingpolyethylene film through a rotogravure printing unit disposed in thebottom of a fountain and running in a bath in the bottom of saidfountain wherein the vehicle is chlorinated solvent and the bath isheated at least approximately to boiling, and condensing in an upperportion of said fountain solvent vapors evolved from said bath and theprinted film.

11. The method of claim wherein said ink oath comprises rubber baseresin, coloring material and chlorinated solvent.

12. The method of claim 10 wherein said bath comprises chlorinatedrubber, butadiene-acrylonitrile copolymer, methyl abietate, diallylphthalate, and coloring material dispersed in chlorinated solvent.

13. Rotogravure printing apparatus comprising a deep fountain, aprinting unit comprising a ro-togravure cylinder and an impression rolidisposed in the bottom of said fountain, and condenser means in the topof said fountain for condensing solvent vapors therein.

14. The apparatus of claim 13 wherein the rotogravure cylinder isheated.

15. Rotogravure printing apparatus comprising a deep enclosed fountain,a rotogravure printing unit disposed in the bottom of said fountain,heater means for heating a bath of ink or coating composition in thebottom of said fountain, condenser mean in the upper portion of saidfountain having at least one extended surface, stationary heater meanshaving a heatable smooth extended surface juxtaposed to said extendedcondensing surface, and guide means for conducting a web after passingthrough said printing unit up and out of said fountain with itsnon-printed side passing over said heated surface.

16. In a rotogravure printing unit having a deep fountain and arotogravure printing unit disposed in the bottom thereof, condensermeans in the upper portion of said fountain providing an extendedcondensing surface, heater means providing an extended heater surfacejuxtaposed to said condensing surface, and guide means for conducting aweb after passing through said printing t2 unit up and out of saidfountainwith its non-printed side passing over said heater surface.

17. In a rotogravure printing unit having a deep fountain and arotogravure printing unit disposed in the bottom thereof, condensermeans in the upper portion of said fountain providing an extendedcondensing surface, heater means providing an extended heater surfacejuxtaposed to said condensing surface, guide means for conducting a webafter passing through said printing unit up and out of said fountainwith its non-printed side passing over said heater surface and secondheater means disposed to pre-heat the Web prior to printing.

18. In a rotogravure printing unit having a deep fountain and arotogravure printing unit disposed in the bottom thereof, condensermeans in the upper portion of said fountain providing an extendedcondensing surface, heater means providing an extended heater surfacejuxtaposed to said condensing surface, and guide means for conducting aweb after passing through said printing unit up and out of said fountainwith its non-printed side passing over said heater surface, saidcondenser surface being so oriented as not to overhang the path of saidprinted Web.

References Cited in the tile of this patent UNITED STATESv PATENTS739,313 How Sept. 22, 1903 1,236,002 Nivling Aug. 7, 1917 1,544,675Moller July 7', 1925' 1,740,979 Golrick Dec. 24, 1929 1,961,827Rutkoskie June 5, 1934 2,223,924 Stephan Dec. 3, 1940 2,290,200 Murch eta1. July 21, 1942 2,304,818 Grupe Dec. 15, 1942 2,396,946 Grupe Mar. 19,1946 2,515,489 Borushko July 18, 1950 2,519,321 Newman Aug. 15, 19502,618,574 Pavlic Nov. 18, 1952 2,659,340 Zinn Nov. 17, 1953 2,675,779Borushko Apr. 20, 1954 2,685,572 Perkins Aug. 3, 1954 2,837,493Schlenker June 3, 1958 2,936,286 Feick May 10, 1960

1. A COMPOSITION COMPRISING ACID-MODIFIED POLYESTER
 8. THE METHOD OF ROTOGRAVURE PRINTING POLYETHYLENE FIBER DYED WITH A DYE OF THE FORMULA FILM WHICH COMPRISES PASSING POLYETHYLENE THROUGH A 